package collection;


import java.util.ArrayList;
import java.util.Collection;

public class CollectionDemo {
    public static void main(String[] args) {
        Collection c=new ArrayList();
        c.add(new Point(1,2));
        c.add(new Point(3,4));
        c.add(new Point(5,6));
        c.add(new Point(1,3));
        c.add(new Point(1,2));
        //[元素1.toString(),元素2.toString(),元素3.toString(),....]
        System.out.println(c);
        /*boolean contains(Object o):
        判断当前集合是否包含给定给定元素o
        判断依据是给定元素是否与当前集合存在equals()比较为true的情况

         */

        Point p=new Point(1,2);
        System.out.println(c.contains(p));

        Point p1=new Point(3,4);
        System.out.println(c.contains(p1));
        /*
        boolean remove(object o):一般不接收boolean结果
        从当前集合中删除与给定元素o的equals()比较为true的元素
         */

        c.remove(p);
        System.out.println(c);

        c.remove(p);
        System.out.println(c);
        //集合中存放的是元素的引用
        Collection cc=new ArrayList();
        Point pp=new Point(1,2);
        cc.add(pp);//将pp添加到了cc，---将pp的引用（地址）装到了cc中
        System.out.println("pp:"+pp);
        System.out.println("cc:"+cc);
        //地址放在栈中，对象放在堆中
        pp.setX(100);
        System.out.println("pp:"+pp);
        System.out.println("cc:"+cc);









        /*
        Collection c=new ArrayList();
        c.add("one");
        c.add("two");
        c.add("three");
        c.add("four");
        c.add("five");
        System.out.println(c);

        System.out.println("size:"+c.size());//输出集合的元素个数 5
        //isEmpty()判断集合是否为空集（size()为0表示空集）
        System.out.println("是否为空集："+c.isEmpty());//false

        c.clear();//清空集合
        System.out.println("集合已清空");
        System.out.println(c);//[]
        System.out.println("size:"+c.size());//0
        System.out.println("是否为空集："+c.isEmpty());//true

         */



    }
}
